Apparatus, system and method for MTC

ABSTRACT

In order for efficiently managing communications between a UE (10) and multiple SCSs (20_1-20_n), the UE (10) includes, in one message, multiple pieces of data to be transmitted to the SCSs (20_1-20_n), and sends the message to an MTC-IWF (30). The MTC-IWF (30) receives the message from the UE (10), and distributes the date to the SCSs (20_1-20_n). Each of the SCSs sends (20_1-20_n), to the MTC-IWF (30), data to be transmitted to the UE (10) and an indicator that indicates for the SCSs (20_1-20 n) the time tolerance until the data is transmitted to the UE (10). The MTC-IWF (30) receives the data and the indicators from the SCSs (20_1-20_n), and determines when to forward the data to the UE (10) based on the indicators.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/126,435, filed Sep. 10, 2018; which is a continuation of U.S.application Ser. No. 15/039,224, filed May 25, 2016; which is a nationalstage entry of Int'l. Appl. No. PCT/JP2014/004561, filed Sep. 4, 2014;which claims priority to Japanese Appl. No. 2013-247474, filed Nov. 29,2013; the contents of all of which are incorporated by reference hereinin their entirety.

TECHNICAL FIELD

The present invention relates to an apparatus, a system and a method forMTC (Machine-Type-Communication), and particularly to communicationsbetween a UE (User Equipment) and multiple SCSs (Service CapabilityServers).

BACKGROUND ART

The architecture of MTC has been studied in 3GPP (3rd GenerationPartnership Project). For example, NPLs 1 and 2 disclose typical MTC-IWF(MTC Inter-Working Function) and SCS. Moreover, NPL 3 discloses that anMTC device can communicate with one or more SCSs.

Note that the MTC device is a UE equipped for MTC and subscribed to MTCservice, which will be sometimes referred to as “MTC UE” or “UE” in thefollowing description.

CITATION LIST Non Patent Literature

-   NPL 1: 3GPP TS 29.368, “Tsp interface protocol between the MTC    Interworking Function (MTC-IWF) and Service Capability Server (SCS)    (Release 11)”, V11.4.0, 2013-09, Clauses 4.2.1 and 4.2.2, pp. 7-8-   NPL 2: 3GPP TS 23.682, “Architecture enhancements to facilitate    communications with packet data networks and applications (Release    11)”, V11.5.0, 2013-09, Clause 4.4.2, pp. 12-13-   NPL 3: 3GPP TS 22.368, “Service requirements for Machine-Type    Communications (MTC); Stage 1 (Release 12)”, V12.2.0, 2013-03,    Clause 5.1.2, pp. 8-9

SUMMARY OF INVENTION Technical Problem

As required in NPL 3, in MTC and service thereof, one UE may subscribeservices from multiple SCSs and need to communicate with the SCSs.

However, the inventors of this application have found that there areseveral problems in this case. For example, one of the problems is thattraffic from the UE to the MTC-IWF is increased with sending messagesone by one. Another problem is that since every time the UE has toperform confidentiality and/or integrity protection for the message, itis power and time consuming.

Accordingly, an exemplary object of the present invention is to providea solution for efficiently managing communications between a UE andmultiple SCSs.

Solution to Problem

In order to achieve the above-mentioned object, an MTC device accordingto first exemplary aspect of the present invention includes: inclusionmeans for including, in one message, multiple pieces of data to betransmitted to a plurality of SCSs or ASs (Application Servers) that cancommunicate with the MTC device through a core network; and send meansfor sending the first message to an MTC-IWF that serves as an enteringpoint in the core network for communications from the SCSs or the ASs.

Further, an MTC-IWF according to second exemplary aspect of the presentinvention serves as an entering point in a core network forcommunications from a plurality of SCSs or ASs that can communicate withan MTC device through the core network. This MTC-IWF includes: receptionmeans for receiving, from the MTC device, one message that includesmultiple pieces of data to be transmitted to the SCSs or the ASs; anddistribution means for distributing the date to the SCSs or the ASs.

Further, an MTC-IWF according to third exemplary aspect of the presentinvention serves as an entering point in a core network forcommunications from a plurality of SCSs or ASs that can communicate withan MTC device through the core network. This MTC-IWF includes: receptionmeans for receiving, from the SCSs or the ASs, multiple pieces of datato be transmitted to the MTC device, and indicators that indicate howlong the SCSs or the ASs can tolerant until respective pieces of thedata are transmitted to the MTC device; and determination means fordetermining when to forward the data to the MTC device based on theindicators.

Further, an SCS according to fourth exemplary aspect of the presentinvention can communicate with an MTC device through a core network.This SCS includes: send means for sending, to an MTC-IWF that serves asan entering point in the core network for communications from the SCS,and one or more different SCSs or ASs, data to be transmitted to the MTCdevice and an indicator that indicates how long the SCS can tolerantuntil the data is transmitted to the MTC device.

Further, a communication system according to fifth exemplary aspect ofthe present invention includes: an MTC device; a plurality of SCSs orASs that can communicate with the MTC device through a core network; andan MTC-IWF that serves as an entering point in the core network forcommunications from the SCSs or the ASs. The MTC device includes, in onemessage, multiple pieces of data to be transmitted to the SCSs or theASs, and sends the message to the MTC-IWF. The MTC-IWF receives themessage from the MTC device, and distributes the date to the SCSs or theASs.

Further, a communication system according to sixth exemplary aspect ofthe present invention includes: an MTC device; a plurality of SCSs orASs that can communicate with the MTC device through a core network; andan MTC-IWF that serves as an entering point in the core network for theSCSs or the ASs. Each of the SCSs or the ASs sends, to the MTC-IWF, datato be transmitted to the MTC device and an indicator that indicates howlong each of the SCSs or the ASs can tolerant until the data istransmitted to the MTC device. The MTC-IWF receives the data and theindicators from the SCSs or the ASs, and determines when to forward thedata to the MTC device based on the indicators.

Further, a method according to seventh exemplary aspect of the presentinvention provides a method of controlling operations in an MTC device.This method includes: including, in one message, multiple pieces of datato be transmitted to a plurality of SCSs or ASs that can communicatewith the MTC device through a core network; and sending the message toan MTC-IWF that serves as an entering point in the core network forcommunications from the SCSs or the ASs.

Further, a method according to eighth exemplary aspect of the presentinvention provides a method of controlling operations in an MTC-IWF thatserves as an entering point in a core network for a plurality of SCSs orASs that can communicate with an MTC device through the core network.This method includes: receiving, from the MTC device, one message thatincludes multiple pieces of data to be transmitted to the SCSs or theASs; and distributing the date to the SCSs or the ASs.

Further, a method according to ninth exemplary aspect of the presentinvention provides a method of controlling operations in an MTC-IWF thatserves as an entering point in a core network for communications from aplurality of SCSs or ASs that can communicate with an MTC device throughthe core network. This method includes: receiving, from the SCSs or theASs, multiple pieces of data to be transmitted to the MTC device, andindicators that indicate how long the SCSs or the ASs can tolerant untilrespective pieces of the data are transmitted to the MTC device; anddetermining when to forward the data to the MTC device based on theindicators.

Furthermore, a method according to tenth exemplary aspect of the presentinvention provides a method of controlling operations in an SCS that cancommunicate with an MTC device through a core network. This methodincludes: sending, to an MTC-IWF that serves as an entering point in thecore network for communications from the SCS, and one or more differentSCSs or ASs, data to be transmitted to the MTC device and an indicatorthat indicates how long the SCS can tolerant until the data istransmitted to the MTC device.

Advantageous Effects of Invention

According to the present invention, it is possible to solve theabove-mentioned problems, and thus to provide a solution for efficientlymanaging communications between a UE and multiple SCSs.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a configuration example of acommunication system according to an exemplary embodiment of the presentinvention.

FIG. 2 is a sequence diagram showing a first example of operations inthe communication system according to the exemplary embodiment.

FIG. 3 is a sequence diagram showing a second example of operations inthe communication system according to the exemplary embodiment.

FIG. 4 is a sequence diagram showing a third example of operations inthe communication system according to the exemplary embodiment.

FIG. 5 is a block diagram showing a business model use case to which thecommunication system according to the exemplary embodiment is applied.

FIG. 6 is a block diagram showing a configuration example of an MTCdevice according to the exemplary embodiment.

FIG. 7 is a block diagram showing a configuration example of an SCSaccording to the exemplary embodiment.

FIG. 8 is a block diagram showing a configuration example of an MTC-IWFaccording to the exemplary embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an exemplary embodiment of an MTC device, an SCS and anMTC-IWF according to the present invention, and a communication systemto which these MTC device, SCS and MTC-IWF are applied, will bedescribed with the accompanying drawings.

In this exemplary embodiment, there will be proposed an efficientsolution for an MTC-IWF to manage and transfer communications between aUE and multiple SCSs.

As shown in FIG. 1 , a communication system according to this exemplaryembodiment includes a MTC UE 10, a core network, and a plurality of SCSs20_1 to 20_n (which will be sometimes collectively denoted by the symbol20).

The core network includes, as its network nodes, an MTC-IWF 30, an MME(Mobility Management Entity), an SGSN (Serving GPRS (General PacketRadio Service) Support Node), an HSS (Home Subscriber Server) 50 and thelike. Note that although the illustration is omitted, the MTC UE 10connects to the core network through a RAN (Radio Access Network), andthe RAN is formed by a plurality of base stations (e.g., eNBs (evolvedNode Bs)). The MME can relay traffic between the RAN and the MTC-IWF 30.The SGSN functions as with the MME. In the following description, theMME and/or the SGSN will be sometimes referred to as “MME/SGSN”, andcollectively denoted by the symbol 40. The HSS 50 manages subscriptioninformation on the MTC UE 10, and the like.

The MTC UE 10 attaches to the core network through the RAN, therebycommunicating with the SCS 20.

The SCS 20 connects to the core network to communicate with the MTC UE10. The MTC UE 10 can host one or multiple MTC Applications. Thecorresponding MTC Applications in the external network are hosted on theSCS 20. Note that although the illustration is omitted, thecommunication system may include a plurality of ASs. As with the SCS 20,each AS can connect to the core network to communicate with the MTC UE10. The MTC Applications can be also hosted on each AS. In the followingdescription, explanations about the SCS 20 can be similarly applied tothose about the AS.

The MTC-IWF 30 serves as an entering point in the core network forcommunication from the SCS 20. Typically, the MTC-IWF 30 transmitstraffic between the MTC UE 10 and the SCS 20.

Next, operation example of this exemplary embodiment will be describedin detail with reference to FIGS. 2 to 4 .

1. Outbound Message

For outbound messages, the MTC UE 10 sends messages to different SCSs inone Data Transmission message. The Data Transmission message sent fromthe MTC UE 10 to the MTC-IWF 30 is confidentiality and/or integrityprotected with the key shared between the MTC UE 10 and the MTC-IWF 30.The Data Transmission sent from the MTC-IWF 30 to the SCS 20 should haveconfidentiality and/or integrity protection, using the security betweenthe MTC-IWF 30 and the SCS 20. The pay load to the SCS 20 isconfidentiality protected with key shared between the MTC UE 10 and theSCS 20. The Data Transmission Ack should have integrity protection.

When the MTC-IWF 30 receives the message, the MTC-IWF 30 performsintegrity check and deciphers the message. The MTC-IWF 30 willdistribute the message to the target SCSs as per MTC UE request.

Specifically, as shown in FIG. 2 , assume that security is establishedbetween the MTC UE 10 and the core network, the MTC UE 10 and theMTC-IWF 30, and the MTC-IWF 30 and the SCS 20 (step S11).

The MTC UE 10 sends data, which the MTC UE 10 wants to send to differentSCSs 20_1 and 20_2, in one message of Data Transmission to the MTC-IWF30 (step S12). The MTC UE 10 encrypts the payload with the keys that theMTC UE 10 shared with the SCSs 20_1 and 20_2. The MTC UE 10 encryptsand/or integrity-protects the message with key that the MTC UE 10 shareswith the MTC-IWF 30. The Data Transmission message can include IDs(identifiers) of the SCSs 20_1 and 20_2 (hereinafter, referred to as“SCS IDs”). In a case where at least one of the SCSs 201 and 20_2provides multiple MTC services, the Data Transmission message canfurther include IDs of the MTC services (hereinafter, referred to as“service IDs”).

The MTC-IWF 30 performs verification and decryption of the message,using the keys that shared between the MTC UE 10 and the MTC-IWF 30(step S13).

According to the SCS ID in the Data Transmission message, the MTC-IWF 30can send the payload to the correct target SCS (step S14). In the casewhere the service ID is included in the Data Transmission message, theMTC-IWF 30 can also send the payload to the correct target SCS accordingto the service ID.

Each of the SCSs 20_1 and 20_2 will send a Data Transmission Ack(acknowledgement) to the MTC-IWF 30. Then, the MTC-IWF 30 can forwardthe Data Transmission Ack messages to the MTC UE 10, separately (stepS15).

In the operations shown in FIG. 2 , multiple pieces of data to differentSCSs are transmitted in one message. Therefore, it is possible to reducebattery consumption of the MTC UE and network resources required fortransmitting the outbound messages.

As substitutes for the operations at above step S15, the communicationsystem can perform operations as shown in FIG. 3 .

Specifically, when the MTC-IWF 30 receives the Data Transmission Ackmessages from the SCSs 20_1 and 20_2 (step S16), the MTC-IWF 30 needsnot to immediately forward the Ack messages to the MTC UE 10.

Thus, the MTC-IWF 30 can hold the Ack messages to the same MTC UE 10,till before the timer for the MTC UE 10 to re-send the Data Transmissionmessage to the SCS 20 (step S17). The timer should be synchronized inthe MTC-IWF 30 and the MTC UE 10. For example, the MTC-IWF 30 starts thetimer when the MTC-IWF 30 received the Data Transmission message fromthe MTC UE 10. Alternatively, the MTC UE 10 can also send the timer tothe MTC-IWF 30 in the Data Transmission message.

In the operations shown in FIG. 3 , a plurality of acknowledgements fromdifferent SCSs are transmitted in one message. Therefore, it is alsopossible to reduce battery consumption of the MTC UE and networkresources required for transmitting the inbound messages.

2. Inbound Message

For inbound messages, some intelligence is needed for the MTC-IWF 30.When the MTC-IWF 30 knows that the target UE subscribes services frommultiple SCSs, the MTC-IWF 30 can wait till more messages come whenthere is no emergency case, and then send the messages in one DataTransmission message. This requires the SCS 20 indicates a deliverytolerance time of the message to the MTC-IWF 30. If the tolerance timershows that the data has to be transmitted immediately, the MTC-IWF 30can forward the Data Transmission in the short tolerance timer order.

The Data Transmission sent from the SCS 20 to the MTC-IWF 30 should haveconfidentiality and/or integrity protection. The Data Transmission sentfrom the MTC-IWF 30 to the MTC UE 10 should have confidentiality and/orintegrity protection. The payload should have confidentiality protectionwith the keys shared between the MTC UE 10 and the SCS 20. The DataTransmission Ack should have integrity protection.

Specifically, as shown in FIG. 4 , assume that security is establishedbetween the MTC UE 10 and the core network, the MTC UE 10 and theMTC-IWF 30, and the MTC-IWF 30 and the SCS 20 (step S21).

The SCS 20_1 sends the Data Transmission to the MTC-IWF 30 (step S22).The SCS 20_1 encrypts the payload with the keys that the SCS 20_1 sharedwith the MTC UE 10. The SCS 20_1 encrypts and/or integrity-protects themessage with key that the SCS 20_1 shares with the MTC-IWF 30.

The SCS 20_2 sends the Data Transmission to the MTC-IWF (step S23). TheSCS 20_2 encrypts the payload with the keys that the SCS 20_2 sharedwith the MTC UE 10. The SCS 20_2 encrypts and/or integrity-protects themessage with key that the SCS 20_2 shares with the MTC-IWF 30.

The MTC-IWF 30 performs verification and decryption of the messages,using the keys that the MTC-IWF 30 shared with the SCSs 20_1 and 20_2.

According to the tolerant timer that each of the SCSs 20_1 and 20_2indicated in the Data Transmission, the MTC-IWF can send the DataTransmission separately (step S26) or in one message (step S27).

Examples of the tolerant timer include:

-   -   the timer can have exact how long the SCS 20 can be tolerant        (can wait), e.g., 60 seconds, 2 minutes, etc.; or    -   the timer can indicate a level, e.g., low, medium, high, then        the MTC-IWF 30 will determine when to forward the message to the        MTC UE 10 according to the network traffic condition.

At step S26, according to the SCS ID in the Data Transmission message,the MTC-IWF 30 sends the Data Transmission from the SCS 20_1 to the MTCUE 10 (step S26_1).

The MTC UE 10 responds with Data Transmission Ack (step S26_2).

According to the SCS ID in the Data Transmission message, the MTC-IWF 30sends the Data Transmission from the SCS 20_2 to the MTC UE 10 (stepS26_3).

The MTC UE 10 responds with Data Transmission Ack (step S264).

Note that the Data Transmission Acks at steps S26_2 and S26_4 can alsobe sent in one message, as with step S12 respectively shown in FIGS. 2and 3 .

Alternatively, at step S27, if the tolerant timer allows, the MTC-IWF 30can forward the data in one Data Transmission message to the MTC UE 10(step S271).

The MTC UE 10 responds with Data Transmission Ack (step S27_2).

Then, the MTC-IWF 30 forwards the Data Transmission Ack to the SCSs 20_1and 20_2, separately (step S28).

In the operation at step S27, multiple pieces of data from differentSCSs to the MTC UE are transmitted in one message. Therefore, it ispossible to reduce battery consumption of the MTC UE and networkresources required for transmitting the inbound messages.

Next, a business model use case to which the communication system isapplied will be described with reference to FIG. 5 .

In an example shown in FIG. 5 , the MTC UE 10 is a vending machine. TheSCSs 20_1 and 20_2 are operated by makers which manufacture products tobe sold by the vending machine. For example, the vending machine can beopened and be a platform that shared by different beverage companies. Inthis case, the vending machine can report to the beverage companies, forreal time market analysis.

Nowadays, it is seen very common that the vending machines are run byone company. Multiple companies share the same vending machine, therebycan reduce their cost and also possibly shorten the supply chain. Inother words, the beverage companies can just focus on what theydo—making drinks.

Moreover, the SCS 20_n is operated by a repair company which repairs thevending machine. The vending machine can report to the repair company incase of anything goes wrong.

Although the illustration is omitted, one of the remaining SCSs may beoperated by an electric power company which delivers electricity to thevending machine. In this case, the vending machine can contact with theelectric power company.

Meanwhile, this use case is only an example, and the idea can beextended to other use cases.

Note that the operators do not need to maintain the MTC-IWF 30. TheMTC-IWF 30 can be owned and run by a 3rd party, such that operator canreduce their cost.

Next, configuration examples of the MTC UE 10, the SCS 20 and theMTC-IWF 30 will be described with reference to FIGS. 6 to 8 . Note thatin the following explanation, there will be described only elementswhich specific to this exemplary embodiment. However, it will beunderstood that the MTC UE 10, the SCS 20 and the MTC-IWF 30 alsoinclude elements for functioning as typical MTC UE, SCS and MTC-IWF,respectively.

As show in FIG. 6 , the MTC UE 10 includes at least an inclusion unit 11and a send unit 12. As shown at step S12 in respective FIGS. 2 and 3 ,the inclusion unit 11 includes, in one Data Transmission message,multiple pieces of data to be transmitted to the SCSs 201 to 20_n.Further, the inclusion unit 11 can includes the SCS ID and the serviceID in the Data Transmission message. Furthermore, the inclusion unit 11can includes, in the Data Transmission message, a value of the timer forthe MTC UE 10 to re-send the Data Transmission message to the SCS 20. Onthe other hand, the send unit 12 sends the Data Transmission message tothe MTC-IWF 30. In addition, the MTC UE 10 can include a reception unit13. As shown at step S17 in FIG. 3 , the reception unit 13 receives,from the MTC-IWF, the Data Transmission Ack message in which the Ackmessages from the SCSs 20_1 to 20_n are included. Note that these units11 to 13 are mutually connected with each other through a bus or thelike. These units 11 to 13 can be configured by, for example, atransceiver which conducts communication with the MTC-IWF 30 through theRAN, and a controller such as a CPU (Central Processing Unit) whichcontrols this transceiver.

As show in FIG. 7 , the SCS 20 includes a send unit 21. As shown atsteps S22 and S23 in FIG. 4 , the send unit 21 sends, to the MTC-IWF 30,the data to be transmitted to the MTC UE 10, and the above-mentionedtolerant timer or level. This send unit 21 can be configured by, forexample, a transceiver which conducts communication with the MTC-IWF 30,and a controller such as a CPU which controls this transceiver.

As show in FIG. 8 , for the outbound messages, the MTC-IWF 30 includesat least a reception unit 31 and a distribution unit 32. As shown atstep S12 in respective FIGS. 2 and 3 , the reception unit 31 receivesthe Data Transmission message from the MTC UE 10. As shown at step S14in respective FIGS. 2 and 3 , the distribution unit 32 distributes, tothe SCSs 20_1 to 20_n, multiple pieces of data included in this DataTransmission message. Moreover, the distribution unit 32 can distinguishthe SCSs to which the multiple pieces of data should be transmitted, bymeans of the SCS ID and the service ID. In addition, the MTC-IWF 30 caninclude a reception unit 33, an inclusion unit 34, and a send unit 35.As shown at step S16 in FIG. 3 , the reception unit 33 receives, fromthe SCSs 20_1 to 20_n, a plurality of acknowledgements of the data. Asshown at step S17, the inclusion unit 34 includes the acknowledgementsin the Data Transmission Ack message, and the send unit 35 sends theData Transmission Ack message to the MTC UE 10. For the inboundmessages, the MTC-IWF 30 includes a determination unit 36. As shown atsteps S22 and S23 in FIG. 4 , the reception unit 33 receives, from theSCSs 20_1 to 20_n, multiple pieces of data to be transmitted to the MTCUE 10, and the above-mentioned tolerant timer or level. As shown at stepS25, the determination unit 36 determines when to forward the data tothe MTC UE 10 based on the tolerant timer or level. If the toleranttimer or level allows, as shown at step S27, the inclusion unit 34includes the data in one Data Transmission message, and the send unit 35sends this Data Transmission message to the MTC UE 10. On the otherhand, if the tolerant timer or level does not allow, as shown at stepS26, the send unit 35 individually sends the data to the MTC UE 10. Notethat these units 31 to 36 are mutually connected with each other througha bus or the like. These units 31 to 36 can be configured by, forexample, a transceiver which conducts communication with the MTC UE 10through the RAN, a transceiver which conducts communication with the SCS20, and a controller such as a CPU which controls these transceivers.

Note that the present invention is not limited to the above-mentionedexemplary embodiment, and it is obvious that various modifications canbe made by those of ordinary skill in the art based on the recitation ofthe claims.

The whole or part of the exemplary embodiment disclosed above can bedescribed as, but not limited to, the following supplementary notes.

(Supplementary Note 1)

UE includes data to different SCSs in one message, to reduce UE batteryconsumption and network resource.

(Supplementary Note 2)

UE indicates the SCS ID and service ID in the Data Transmission, suchthat MTC-IWF can distinguish to which SCS it should transfer.

(Supplementary Note 3)

MTC-IWF distributes the data transmission to different target SCSs.

(Supplementary Note 4)

SCS indicates a tolerant timer in the data transmission message, suchthat MTC-IWF can determine whether the data should be transmitted to UEimmediately or it can transmit payload from more than SCSs to target UE.

(Supplementary Note 5)

The intelligence of MTC-IWF delivering data to and from different UEs orSCSs can reduce network traffic.

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2013-247474, filed on Nov. 29, 2013, thedisclosure of which is incorporated herein in its entirety by reference.

REFERENCE SIGNS LIST

-   -   10 MTC UE    -   11, 34 INCLUSION UNIT    -   12, 21, 35 SEND UNIT    -   13, 31, 33 RECEPTION UNIT    -   20, 20_1-20_n SCS    -   30 MTC-IWF    -   32 DISTRIBUTION UNIT    -   36 DETERMINATION UNIT    -   40 MME/SGSN    -   50 HSS

The invention claimed is:
 1. A network node in a mobile communicationsystem comprising a User Equipment (UE), a mobility management node, anda plurality of network servers, the network node comprising: one or morememories storing instruction; and one or more processors configured toexecute the instructions to: receive, from the mobility management node,one first message comprising information for identifying the pluralityof network servers based on a request from the UE, identify theplurality of network servers based on the information, send atransmission message to each of the plurality of network servers,receive a transmission response message from each of the plurality ofnetwork servers, and send, to the mobility management node, onereception message comprising service identifications (IDs).
 2. Acommunication method of a network node in a mobile communication systemcomprising a User Equipment (UE), a mobility management node, and aplurality of network servers, the communication method comprising:receiving, from the mobility management node, one first messagecomprising information for identifying the plurality of network serversbased on a request from the UE; identifying the plurality of networkservers based on the information; sending a transmission message to eachof the plurality of network servers; receiving a transmission responsemessage from each of the plurality of network servers; and sending, tothe mobility management node, one reception message including serviceidentifications (IDs).